ES2721881T5 - Cutting insert and cutting tool - Google Patents

Description

DESCRIPTION

Cutting insert and cutting tool

field of invention

The present invention relates to a rotary metal cutting tool and a reversible indexable cutting insert, for metal cutting processes in general and for milling operations in particular.

Background of the invention

Metal cutting tools used in milling operations, including cutting inserts that are removably secured in a cutting body, have long been provided with a suitably hard material, i.e., cemented carbide, in metal cutting tools. around the cutting edge, where the cutting body, which is made from a less hard material, is reusable after discarding a worn or damaged cutting insert.

The cutting inserts are held within insert receiving pockets that are located on the periphery of the tool body, to hold and support the cutting inserts in both axial and radial directions during operation (eg, milling operation).

United States Patent no. 3,541,655 issued to Stier, and entitled "Indexable and Reversible Cutting Inserts", is directed to a cutting insert with two identical and unequal parallel polygonal end faces. The end faces are rotated relative to each other. A trapezoidal side face extends between each side of one of the polygonal end faces and a respective side of the other end face. Each two adjacent side faces are formed with two opposite trapezoids. Each trapezoidal side face forms an acute angle with one of the end faces, while it forms a complementary obtuse angle with the other end face.

United States Patent no. 7,037,051 issued to Wermeister, and entitled "Cutting Insert for Turning and Milling", is directed to a cutting insert with first and second polygonal-shaped main faces that are arranged substantially parallel to one another. A side face structure interconnects the first and second major faces to define a peripheral edge. The principal faces include projections that extend toward the peripheral edge. Each projection is formed by a portion of the first major surface, which defines a relief surface; a portion of the side face structure, which defines a sloped surface; and a peripheral edge portion, defining a cutting edge. The cutting insert includes support surfaces that are defined by a portion of the second major face and by portions of the lateral surface structure other than the rake surface.

United States Patent no. 5,957,629 issued to Hessman, and entitled "Fine Milling Cutting Insert", addresses a double-sided milling cutting insert. The insert includes two parallel main surfaces that rotate 90° relative to each other. Each main surface includes four operative cutting corners. At each cut corner there are two beveled surfaces that are at an angle to the plane of the main surface. In addition, four side surfaces of the insert meet at an angle that extends between the main surfaces.

United States Patent no. 4,294,566 issued to Boone, and entitled "Fight Edge Positive Chip Control Insert", addresses a cutting insert with eight positive cutting edges and a rectangular prismatic configuration. The insert has a pair of opposed primary faces, and four rectangular lateral faces, each of which has a pair of coplanar flats at opposite corners thereof, for positive insert locating and holding. Each side face also has a laterally opposed pair of positive bevel facets formed thereon, and which intersect the respective primary faces in an inward slope to define neutral cutting edges for the insert. An elongated groove extends intermediate the beveled facets of each side face parallel to the neutral cutting edges.

Document EP 2198997 A2 shows an indexable reversible cutting insert according to the preamble of claim 1.

It is an object of the present invention to provide an improved indexable reversible cutting insert and a cutting tool therefor, the cutting insert having a plurality of cutting edges, which can be employed at a positive axial slope and a negative radial slope relative to each other. to a work piece.

Brief description of the invention

In accordance with the present invention, there is provided an indexable reversible cutting insert according to claim 1.

According to a preferred embodiment of the present invention, there is provided a cutting tool according to claim 9.

According to another embodiment of the present invention, there is provided a cutting tool body according to claim 12.

Brief description of the figures

For a better understanding, the invention will now be described, by way of example only, with reference to the accompanying figures in which chain dashed lines represent cut-offs for partial views of a member and in which:

Figure 1A is a perspective view of a cutting tool in accordance with some embodiments of the present invention;

Figure 1B is an exploded side view of the cutting tool shown in Figure 1A, revealing an insert pocket;

Figure 1C is a perspective view of the insert pocket shown in Figure 1B;

Figure 1D is a front view of the insert pocket shown in Figure 1B;

Figure 1E is a cross-sectional view of the insert pocket shown in Figure 1D, taken along the line V-V;

Figure 2A is a perspective view of a cutting insert in accordance with a first embodiment of the present invention;

Figure 2B is a top view of the cutting insert shown in Figure 2A;

Figure 2C is a cross-sectional view of the cutting insert shown in Figure 2B, taken along the line I-I;

Figure 2D is a cross-sectional view of the cutting insert shown in Figure 2B, taken along the line M-M;

Figure 3A is a perspective view of a cutting insert in accordance with a second embodiment of the present invention;

Figure 3B is a top view of the cutting insert shown in Figure 3A;

Figure 3C is a cross-sectional view of the cutting insert shown in Figure 3B, taken along the line MI-MI; and

Figure 3D is a cross-sectional view of the cutting insert shown in Figure 3B, taken along line IV-IV.

Detailed description of the invention

The present invention relates to an indexable reversible cutting insert, having two opposed polygonally shaped end surfaces and a peripheral surface extending between them. The invention also relates to a cutting tool for employing the cutting inserts at a positive axial draft angle and a negative radial draft angle when engaged in a workpiece.

Reference is first made to Figure 1A which depicts a cutting tool 100 in accordance with some embodiments of the present invention. Cutting tool 100 includes a tool body 110. Cutting tool 100 has a longitudinal axis of rotation B1, a front end 102, and a trailing end 104. Tool body 110 includes a plurality of cutting inserts. 20, 130 that are mounted on it. Each of the cutting inserts 20, 130 sits within a respective insert pocket 106 and is retained by a respective clamping screw 108.

Reference is now made to Figures 2A-2D, which depict a cutting insert 20 in accordance with a first embodiment of the present invention, including a polygonally shaped first end surface 22 and an opposing polygonally shaped second end surface. 24, identical and generally parallel to the first end surface 22. The first end surface 22 defines a first end plane P1 and the second end surface 24 defines a second end plane P2, the first and second end planes P1 , P2 are parallel to each other. The first end plane P1 may correspond to a flat surface that rests on the first end surface 22 while the second end plane P2 may correspond to a flat surface on which the second end surface 24 rests. Therefore, the first end plane P1 is generally parallel to the first end surface 22 and a plurality of cutting edges (described below) that are formed at a periphery of the first end surface 22 may, in some embodiments, all be positioned on the first end plane P1 or have some other common positional relationship with respect to the first end plane P1. The second end plane P2 has a similar relationship to the second end surface 24.

The cutting insert 20 exhibits rotational symmetry about an insert axis B2. The second end surface 24 rotates about the insert axis B2, relative to the first end surface 22. The first end surface 22 and the second end surface 24 both have a polygonal shape of an octagon. uneven, such that the second end surface 24 is rotated relative to the first end surface 22, by an angle of 45°. Since the two end surfaces 22, 24 are identical, although rotated relative to each other, only one of them will be described in detail.

Cutting insert 20 further includes a peripheral side surface 26 that extends between opposed end surfaces 22, 24. Peripheral side surface 26 includes a plurality of peripheral side portions 30, 32 that are arranged circumferentially in alternate orientation. Each of the first orientation peripheral side portions 30 is a reverse copy (ie, an upside down copy) of its adjacent second orientation peripheral side portion 32 .

The intersection of the first end surface 22 with the peripheral side surface 26 forms a first continuous circumferential cutting edge 46. The intersection of the second end surface 24 with the peripheral surface 26 forms a second continuous circumferential cutting edge 48. The first circumferential cutting edge 46 is formed along the entire intersection of first end surface 22 with peripheral side surface 26. First circumferential cutting edge 46 includes four identical cutting edge sections 50. Each edge section The cutting edge 50 extends between two vertices of the polygonal shape of the first end surface 22. Each cutting edge section 50 includes a first cutting edge 58 and a second cutting edge 60. Each of the peripheral side portions 30 and 32 extends between one of the first cutting edges on either of the end surfaces 22, 24, and one of the second cutting edges. on the other end surface. As shown in Figure 2A, each first peripheral side portion 30 extends between one of the first cutting edges 58 that are located on the first end surface 22, and one of the second cutting edges 74 that are located on the first end surface 22. second end surface 24. Each of the peripheral side portions 32 extends between one of the first cutting edges 52 located on the second end surface 24, and one of the second cutting edges 60 located on the second end surface 24. first end surface 22.

Since the polygonal shape of each of the two end surfaces 22, 24 is an unequal octagon, each end surface 22, 24 has four long sides and four short sides, which are arranged alternately along its respective edge. circumferential cut 46, 48. In each cutting edge section 50, the first cutting edge 58 is located on one of the long sides of the unequal octagon, while the second cutting edge 60 is located on one of the short sides of the unequal octagon. uneven octagon. Each first cutting edge 58 has a first length A, and each second cutting edge 60 has a second length W. Thus, the first length A of each first cutting edge 58 is preferably greater than the second length W of each second edge. 60. According to a specific embodiment of the present invention, the ratio of the second length W to the first length A (ie, W/A), is in the range of 1/10<W/A< 2/3. According to another specific embodiment of the present invention, the ratio W/A=2/3. As shown in Figure 2B, two imaginary lines L1, L2, containing the first cutting edges 58 of two adjacent cutting edge sections 50, form a right angle there between.

Cutting insert 20 also includes a central through-hole 62 that extends between, and opens toward, both end surfaces 22, 24. First end surface 22 includes an insert contact surface 64 that substantially surrounds the opening of the cutting insert. through hole 62, and extending toward each of the second cutting edges 60 of the first end surface 22. Since each of the peripheral side portions 30, 32 extends between one of the first cutting edges 58, 52, at any one of the end surfaces 22, 24, and one of the second cutting edges 60, 74, at the other end surface, a first operative cutting edge 58 is therefore supported by a portion of the contact surface of the insert 64 on the opposite side of the cutting insert 20, thus providing greater resistance during metal cutting operations. First peripheral side portions 30 alternate in the circumferential direction of the insert with second peripheral side portions 32. As shown in Figure 2A, each first peripheral side portion 30 includes a first subface 70 and a second subface 72 that intersect at a line N1, in an intermediate plane P3. The first subface 70 and the second subface 72 are located on non-coplanar surfaces. Each peripheral side portion 32 includes a first subface 66 and a second subface 68 that intersect at a line N2, at an intermediate plane P4. The first subface 66 and the second subface 68 are also located on non-coplanar surfaces. Therefore, the two subfaces belonging to each of the first peripheral side portions 30 intersect at lines N1 which together define the first intermediate plane P3, while the two subfaces belonging to each of the second peripheral side portions 32 intersect. intersect at lines N2 which together define the second plane P4.

As shown in Figures 2C and 2D, each of the intermediate planes P3 and P4 is located between, and is parallel to, the end surfaces 22 and 24. The intermediate planes P3, P4 are parallel and spaced apart from each other, so so that a first distance di between the intermediate planes P3, P4 and the first and second end surfaces 22, 24, respectively, is less than half the thickness distance H between the end surfaces 22 and 24 (i.e., H is the thickness of the cutting insert 20).

The subfaces 70, 72 of each of the first peripheral side portions 30 intersect at the first line Ni which lies at a first distance di from the first end plane P1 and a second distance d2 from the second end plane P2, while the subfaces 70, 72 of each of the second peripheral side portions 32 intersect at the second line N2 which is located at a first distance d1 from the second end plane P2 and a second distance d2 from close-up of end P2. Thus, as seen in Figures 2C and 2D, each plane P3, P4 is located at a first distance d1 from one of the end surfaces and a second complementary distance d2 from the other end surface.

Each of the first subfaces extends between a respective one of the first cutting edges and one of the intermediate planes, which forms a first internal angle of the insert a with an end plane. As shown in Figure 2C, the first subface 70 forms a first internal angle of the insert a with a first end plane P1. Similarly, as shown in Figure 2D, the first subface 66 forms a first internal insert angle a with a second end plane P2.

It will be appreciated that the use of the terms "internal angle" and "external angle" throughout the description and claims refers to an angle between two planar surface components, which are measured internally and externally to the member on which they are attached. form the surface components, respectively.

Each of the second sub-faces extends between a respective one of the second cutting edges and one of the intermediate planes, which forms a second internal angle of the insert 0 with an end plane. As shown in Figure 2C, the second subface 72 forms a second internal angle of the insert 0 with the second end plane P2. Similarly, as shown in Figure 2D, the second subface 68 forms the second internal angle of the insert 0 with the first end plane P1.

According to the present invention, the second insert internal angle 0 is an acute angle, and different from the first insert internal angle a. Since the first subface and the second subface of the same peripheral side portion lie on non-coplanar surfaces and the end planes P1 and P2 are parallel to each other, the sum of the first insert internal angle a and the second insert internal angle 0 is different from 180° (that is, a+0£180°). According to a specific embodiment of the present invention, the first insert internal angle a is in the range of 85° to 100°, and the second insert internal angle 0 is in the range of 65° to 83°. According to a specific embodiment of the present invention, the first internal angle of the insert a is an angle of 95°, and the second internal angle of the insert 0 is an angle of 77°.

These typical values of the first internal angle of the insert a and the second internal angle of the insert 0 of the cutting insert 20 allow positioning of the cutting insert 20 at a positive axial draft angle, relative to the surface of the workpiece during grinding. operation. The axial draft angle is measured between a plane of an end surface of the cutting insert and a plane perpendicular to the bottom end surface of the tool body and including therein the lower cutting edge of the cutting insert. In addition, these geometric features of cutting insert 20 allow for positioning of cutting insert 20 at a negative radial rake angle, during operation in a workpiece. Radial draft angle is measured between the radius of the rotary cutting tool and the lower cutting edge of the cutting insert. Such positioning of the cutting insert can be considered as a positive-negative insert geometry, which introduces significant advantages to an operating cutting tool, such as reduced energy required to operate the cutting tool, better chip removal, and Similar.

The first end surface 22 includes a plurality of rake depressions 80, each rake depression having an elongated shape and located substantially along a respective first cutting edge, extending inwardly from the respective first cutting edge. . As shown in Figures 2B and 2C, each rake depression 80 lies along the first cutting edge 58, and extends inwardly from the first cutting edge 58. When the cutting insert 20 is used in the metal cutting, the first cutting edge 58 contacts the surface of a workpiece to remove material therefrom. The material to be removed, in the form of metal shavings, flows along the rake depression 80, and can then be removed from the cutting area.

It should be noted that cutting insert 20 is an indexable and reversible cutting insert, such that any of the cutting edge sections 50 on the first end surface 22, as well as cutting edge sections that are located on the second end surface 24, they can also be used in metal cutting. Once a certain cutting edge portion of the cutting insert is worn, the cutting insert is rotated or flipped (either by an operator or automatically), in order to employ a new cutting edge portion. It should further be noted that the numerals "i"-"4" appearing on the first end surface 22 in Figures 2A and 2B are index numbers, to indicate to an operator of the cutting insert 20, which cutting edge section is being used. Additional number signs "5"-"8" appear in similar locations on end surface 24. By following the numbers on end surfaces 22 and 24, the operator of cutting insert 20 can confirm which of the eight cutting sections cutting edge is being used in each operation.

Although the presently described cutting insert includes end surfaces in the shape of unequal octagons, such that each circumferential cutting edge includes four first and four second cutting edges. cutting edges, it will be appreciated that the end surface can have any other polygonal shape such that each circumferential cutting edge would include N cutting edge sections, i.e. N first cutting edges and N second cutting edges, in where N is a positive integer, and N>2. Such a cutting insert would also include 2N peripheral side portions.

Reference is now made to Figures 3A-3D, which depict a cutting insert 130, in accordance with another embodiment of the technique described. Cutting insert 130 includes a polygon-shaped first end surface 132 and an opposite polygon-shaped second end surface 134 identical to and parallel to first end surface 132. Cutting insert 130 exhibits rotational symmetry about an axis. of insert B3. The second end surface 134 rotates about the insert axis B3, relative to the first end surface 132. The first end surface 132 and the second end surface 134 both have a polygonal shape of an unequal octagon, such that the second end surface 134 is rotated relative to the first end surface 132, through an angle of 45°. Cutting insert 130 has a median plane M, which is located between end surfaces 132 and 134, and is parallel to end surfaces 132 and 134. As seen in Figures 3C and 3D, the distances d1 and d2 from the median plane M to the two end planes S1 and S2 have a common distance d, and therefore the median plane M is equally distant from each of the end surfaces 132 and 134.

Cutting insert 130 further includes a peripheral side surface 136 extending between end surfaces 132 and 134. Peripheral side surface 136 includes a plurality of peripheral side portions 140 and 142, which are arranged circumferentially in alternate orientation. Each of the first orientation peripheral side portions 140 is a reverse copy (ie, an upside-down copy) of its adjacent second orientation peripheral side portion 142.

The intersection of the first end surface 132 with the peripheral side surface 136 forms a first continuous circumferential cutting edge 135. The intersection of the second end surface 134 with the peripheral side surface 136 forms a second continuous circumferential cutting edge 137. The first circumferential cutting edge 135 includes four identical cutting edge sections 170. Each cutting edge section 170 extends between two vertices of the polygonal shape of the first end surface 132. Each cutting edge section 170 includes a first cutting edge 161 and a second cutting edge 163.

Each of the peripheral side portions 140 and 142 extends between one of the first cutting edges on either one of the end surfaces 132, 134, and one of the second cutting edges on the other end surface. As shown in Figure 3A, each peripheral side portion 140 extends between one of the first cutting edges 161 located on the first end surface 132, and one of the second cutting edges 167 located on the second. end surface 134. Each of the peripheral side portions 142 extends between one of the first cutting edges 165 located on the second end surface 134, and one of the second cutting edges 163 located on the first end surface 132. Each peripheral side portion 142 includes a first subface 156 and a second subface 158, and each peripheral side portion 140 includes a first subface 160 and a second subface 162. The first subface 156 and second subface 158 are located at non-coplanar surfaces, and the first sub-face 160 and the second sub-face 162 lie on non-coplanar surfaces.

Cutting insert 130 is substantially similar to cutting insert 20, described herein, except that the subfaces of the peripheral side portions intersect at a single median plane M. Each of the first subfaces of the surface peripheral lateral 136 extends between one of the first cutting edges and the median plane M, which forms a first internal angle of the insert 9 with an end plane. As shown in Figure 3C, the first subface 160 forms a first internal angle of the insert 9 with the first end plane S1 which is defined by the first end surface 132. Similarly, as shown in Figure 3D, the first subface 156 forms a first internal angle of the insert 9 with the second end plane S2 which is defined by the second end surface 134.

Each of the second subfaces of the peripheral lateral surface 136 extends between one of the second cutting edges and the median plane M, which forms a second internal angle of the insert 9 with an end plane. As shown in Figure 3C, the second subface 162 forms a second internal angle of the insert 9 with the second end plane S2. Similarly, as shown in Figure 3D, the second subface 158 forms a second internal angle of the insert 9 with the first reference plane S1.

With further reference to Figures 1A-1E, the tool body 110 includes a plurality of cutting inserts 20 that are mounted therein, wherein each cutting insert sits within a respective insert pocket 106 and is retained. by a respective set screw 108. As best shown in Figures 1B and 1C, insert pocket 106 includes a preferably flat pocket contact surface 112 defining a contact plane P5, a threaded hole 120, a first and second pocket receiving side walls 1141 and 1142, and a free pocket surface 126.

Threaded hole 120 opens into pocket contact surface 112. Pocket receiving sidewalls 1141, 1142 extend from pocket contact surface 112 in a general tangential direction of tool body 110. Since the two Pocket receiving side walls 1141, 1142 are identical (however angled relative to each other), only one of which will be described in detail. The free pocket surface 126 includes a first end 127 that mates with the pocket contact surface 112, and a second end 129. The free pocket surface 126 extends from the pocket contact surface 112 along the end. bottom 102 (Figure 1A) of tool body 110, as it tapers in a rearward direction (i.e., away from the seat of cutting insert 20), toward second end 129. Free pocket surface 126 provides clearance for the operative cutting edge 58, when the cutting insert 20 is operative against a workpiece.

Tool body 110 may optionally include a coolant channel 115, which opens adjacent insert pocket 106, to provide coolant fluid to operating cutting edge 58 of cutting insert 20, during operation against a workpiece. . Such a coolant fluid may be necessary or desirable in order to reduce the heat that is generated in the contact area of the cutting edge and the workpiece during the metal cutting operation.

The first pocket receiving sidewall 1141 further includes a first flat sidewall section 1161. As best shown in Figure IE, the first flat sidewall section 1161 forms an insert receiving outer angle p with a plane P6, which intersects the first planar sidewall section 1161, and is parallel to the contact plane P5. The first pocket receiving sidewall 1141 further includes a second flat sidewall section 1181, which intersects the first flat sidewall section 1161. The second flat sidewall section 1181 extends toward contact plane P5, to form an external angle of the acute pocket $ with the contact plane P5. The second pocket receiving sidewall 1142 similarly includes the first and second planar sidewall sections 1162, 1182.

As best shown in Figure 1D, in a front view of the insert pocket 106, each of the two respective pocket receiving side walls 1141, 1142 contains an imaginary line L3, L4, respectively. The imaginary lines L3, L4 are substantially at right angles to and with each other, and therefore the pocket receiving side walls 1141, 1142 themselves can be considered to be at right angles with each other. The angle y substantially conforms to the right angle formed between the two imaginary lines L1 and L2 (shown in Figure 2B) containing the first cutting edges 58 of two adjacent cutting edge sections 50. It should be noted that the angle y between the imaginary lines L3 and L4 may be slightly less than a right angle (eg ^y = 89.5°), in order to reduce the contact surface between the first pocket side wall sections and the respective first sub-face of the cutting insert, when the cutting insert seats within the pocket.

The cutting insert 20 seats within the insert pocket 106 such that the insert contact surface of the second end surface 24 bears against the pocket contact surface 112. In addition, each of the first subfaces of the first two peripheral side portions 30 (Figure 2A), bear against a respective one of the first side wall sections 1161 and 1162. In this way, two of the first peripheral side portions 30 are held with respect to the receiving side walls 1141 and 1142, in a dovetail fashion, due to their corresponding conformal shape. Additionally, set screw 108 passes through central through-hole 62 of cutting insert 20 and threadedly engages threaded hole 120 in pocket 106, in order to secure cutting insert 20 in place for operation. .

The external angle of the acute pocket $ is slightly smaller than the second internal angle of the insert 0, in order to avoid contact between the second side wall section of the pocket and the respective second sub-face of the peripheral side portion of the insert. The outer insert receiving angle p is slightly larger than the first inner insert angle a, in order to reduce the contact surface between the first pocket side wall section and the respective first subface of the cutting insert. In a specific embodiment of the invention, the external receiving angle of the insert p is greater than the second internal angle of the insert a by 0.5°. It should further be noted that the shape of each of the receiving side walls 1141 and 1142 substantially conforms to the shape of the respective first peripheral side portion 30.

Claims (12)

An indexable reversible cutting insert (20, 130) having an insert axis (B2, B3) about which the insert exhibits rotational symmetry, and comprising: a polygonally shaped first end surface (22, 132) defining a first end plane (P1, S1) and a polygonally shaped second end surface (24, 134) defining a second end plane (P2, S2 ), the first and second end planes (P1, S1, P2, S2) are identical and parallel to each other; a peripheral side surface (26, 136) extending between the end surfaces (22, 24, 132, 134), the peripheral side surface (26, 136) including first peripheral side portions (30, 140) staggered in the circumferential direction with the second adjacent peripheral side portions (32, 142); a first edge (46, 135) that is formed along the entire intersection of the first end surface (22, 132) with the peripheral side surface (26, 136), the first edge is a first circumferential cutting edge continuous and comprising a plurality of first cutting edges (58, 161) alternated with a plurality of second cutting edges (60, 163); a second edge (48, 137) that is formed along the entire intersection of the second end surface (24, 134) with the peripheral side surface (26, 136), the second edge is a second circumferential cutting edge continuous and comprising a plurality of first cutting edges (52, 165) alternated with a plurality of second cutting edges (74, 167); where each of the first peripheral side portions (30, 140) comprises a first subface (70, 160) that forms a first internal angle of the insert (a, 9) with the first end plane (P1, S1) and a second subface (72, 162) forming an acute internal angle of the second insert (0, 9) with the second end plane (P2, S2), the first subface and the second subface of each first peripheral side portion (30, 140) are intersect in a first line (N1) in an intermediate plane (P3) that is located between and parallel to the first and second end planes (P1, P2, S1, S2) and that is at a first distance (d1, d) from the first end plane (P1, S1) and at a second distance (d2, d) from the second end plane (P2, S2); where each of the second peripheral side portions (32, 142) comprises a first subface (66, 156) that forms a first internal angle of the insert (a, 9) with the second end plane (P2, S2) and a second subface (68, 158) forming an acute internal angle of the second insert (0, 9) with the first end plane (P1, S1), the first subface and the second subface of each second peripheral lateral portion (32, 142) are intersect in a second line (N2) in an intermediate plane (P4) that is located between and parallel to the first and second end planes (P1, P2, S1, S2) and that is at the first distance (d1, d) from the second end plane (P2, S2) and at the second distance (d2, d) from the first end plane (P1, S1). the indexable reversible cutting insert (20, 130), further comprising: a central through hole (62) extending between and opening into the end surfaces (22, 24, 132, 134); an insert contact surface (64) that is formed at each end surface (22, 24, 132, 134); where: each of the first peripheral side portions (30, 140) extends from a first cutting edge (58, 161) associated with the first end surface (22, 132) to a second cutting edge (74, 167) associated with with the second end surface (24, 134); and each of the second peripheral side portions (32, 142) extends from a first cutting edge (52, 165) associated with the second end surface (24, 134) to a second cutting edge (60, 163) associated with with the first end surface (22, 132), and wherein each of the first cutting edges (52, 58, 161, 165) has a first length A and each of the second cutting edges (60, 74, 163, 167) has a second length W, and where the first length A is greater than the second length W characterized because the second end surface (24, 134) is rotated relative to the first end surface (22, 132) about the insert axis (B2, B3). The cutting insert (20) of claim 1, wherein the subfaces (66, 68, 70, 72) of the adjacent peripheral side portions (30, 32) intersect in different spaced apart intermediate planes (P3, P4), and where each of the separated intermediate planes (P3, P4) is separated by a first similar distance (d1) from its nearest end plane (P1, P2). The cutting insert (20) of claim 2, wherein the two end surfaces (22, 24) are separated by a distance of thickness H, and wherein the first distance (d1) is less than half of thickness distance H. The cutting insert (130) of any one of claims 1 to 2, wherein the subfaces (156, 158, 160, 162) of each peripheral side portion (140, 142) intersect in a single median plane (M ), equidistant from the end planes (S1, S2). The cutting insert (20, 130) of any one of claims 1 to 5, wherein each circumferential cutting edge (46, 48, 135, 137) includes N first cutting edges (52, 58, 161, 165). ) and N second cutting edges (60, 74, 163, 167), N is a positive integer greater than 2. The cutting insert (20, 130) of any one of claims 1 to 5, wherein the polygonal shape of each of the end surfaces (22, 24, 132, 134) has an unequal octagonal shape. The cutting insert (20, 130) of any one of claims 1 to 6, wherein the first internal angle of the insert (a, 9) is in the range of 85° to 100°, and the second internal angle of the insert (0, 9) is in the range of 65° to 83°. The cutting insert (20, 130) of any one of the preceding claims, wherein the first length A and the second length W define a W/A ratio, and wherein the W/A ratio is in the range of 1 /10<W/A<2/3. 9. A cutting tool (100) having a longitudinal axis of rotation (B1), the cutting tool (100) comprising: a tool body (110) having at least one insert pocket (106) that is formed at a front end (102) of the tool body (110); and a cutting insert (20, 130) according to any of claims 1 to 8 retained in at least one insert pocket (106), where: said at least one insert pocket (106) comprises: a pocket contact surface (112) defining a contact plane (P5); a threaded hole (120) that ends in the contact surface of the pocket (112); two pocket receiving sidewalls (1141, 1142) extending from the contact plane (P5), each of the pocket receiving sidewalls (1141, 1142) includes: a first flat sidewall section (1161, 1162 ) that forms an external insert-receiving angle (p) with a plane (P6) that intersects the first flat sidewall section (1161, 1162) and is parallel to the contact plane (P5); and a second flat sidewall section (1181, 1182) intersecting the respective first flat sidewall section (1161, 1162), and extending towards the contact plane (P5) to form an external angle of the acute pocket ($) with the same; one of the two contact surfaces of the insert (64) adjoins the contact surface of the pocket (112); the first sub-faces (66, 70, 156, 160) of two peripheral side portions (30, 32, 140, 142) of the cutting insert (20, 130) adjoin the respective sections of the first side wall (1161, 1162) , in a dovetail fashion; and A set screw (108) passes through the central through hole (62) of the cutting insert (20, 130) and threadedly engages the threaded hole (120) of the insert pocket (106). The cutting tool (100) of claim 9, wherein the first two sub-faces (66, 70, 156, 160) contact the respective sections of the first side wall (1161, 1162), in a manner of dovetail, are associated with the same end surface (22, 24, 132, 134) of the cutting insert (20, 130). The cutting tool (100) of any one of claims 9 to 10, wherein in a front view of the at least one insert pocket (106), the two respective pocket-receiving sidewalls (1141, 1142) form a substantially right angle (y) between them. 12. A cutting tool body (110) having a longitudinal axis of rotation (B1), the cutting tool body (110) having a front end (102) with at least one insert pocket (106) which is formed in this, where: said at least one insert pocket comprises: a pocket contact surface (112) defining a contact plane (P5); a threaded hole (120) that ends in the contact surface of the pocket (112); and two pocket receiving sidewalls (1141, 1142) extending from the contact plane (P5), characterized in that each of the pocket-receiving sidewalls (1141, 1142) include: a first flat sidewall section (1161, 1162) that forms an insert-receiving outer angle (p) with a plane (P6) intersecting the first side wall section flat (1161, 1162) and is parallel to the contact plane (P5); and a second flat sidewall section (1181, 1182) intersecting the respective first flat sidewall section (1161, 1162), and extending towards the contact plane (P5) to form an external angle of the acute pocket ($) with the same; wherein in a front view of each insert pocket (106), the two pocket receiving side walls (1141, 1142) form a substantially right angle (y) to each other, wherein a cutting insert (20, 130) according to any of claims 1 to 8 is retained in at least one insert pocket (106).